JP5189273B2 - One-way clutch - Google Patents

Description

  The present invention relates to a one-way clutch that transmits only a one-way torque of an input member to an output member, and more particularly, to a one-way clutch characterized by water-resistant grease sealed in the device.

With the widespread use of FF (front engine / front drive) vehicles aimed at miniaturization and weight reduction, and further expansion of living space, automobiles are being forced to reduce their engine rooms. For this reason, electrical equipment accessories for automobiles are further reduced in size and weight, and higher performance and higher output are increasingly required.
As a typical automotive electrical accessory that operates via a one-way clutch, a fan coupling device that performs optimal ventilation corresponding to the engine temperature and the rotation of the engine is received by the belt to generate electricity and power to the electric load of the vehicle And an alternator that charges the battery. These are used to efficiently use the rotational torque of the engine through a one-way clutch that is connected only when the engine is in a predetermined output state. One-way clutches mounted on automobile electrical accessories are frequently attached and detached from the engine output shaft, and because the rotational speed when connected to the engine output shaft is high, load load, generated heat and vibration, etc. The conditions of use are becoming stricter with higher performance and higher output of automobiles.

When the usage conditions of the one-way clutch become severe in this way, when the one-way clutch is overrun, the rolling surface of each roller of the one-way clutch and the rolling surface of the outer ring for the clutch, and the shaft to which the one-way clutch is attached. Is likely to be peeled off with a change in white structure on the rolling surface of the inner ring for clutch connected to. For this reason, it is desired to use a grease that can prevent the occurrence of peeling as the grease to be enclosed in the space in which the rollers are installed.
Conventionally, in a one-way clutch, a grease using ether oil as a base oil (see Patent Document 1), a grease using a pressure viscosity coefficient equal to or greater than a predetermined value (see Patent Document 2), or 40 A grease using a synthetic oil base oil having a kinematic viscosity at 60 ° C. of 60 mm ² / sec or less (see Patent Document 3) is known.

  Further, these one-way clutches are mounted on an automobile electrical accessory such as an alternator and are disposed in an engine room. The engine room is not completely sealed for reasons such as cooling, and water can enter when the car is running due to rain water or a splash of water pool. For this reason, the one-way clutch is provided with a seal mechanism to prevent dust from entering from outside and leakage of grease, but it is difficult to completely prevent water from entering. Particularly in recent years, due to the demand for low fuel consumption, there is a tendency to reduce the tightening force of the seal in order to reduce the rotational torque, which makes it easy for water to enter.

When water enters the space where the rollers of the one-way clutch are installed, the following problems arise even when the above-described grease is used. When water droplets enter the load area, the oil film is interrupted, which is disadvantageous in terms of lubricity. When the oil film is interrupted, metal contact occurs, and there is a risk that wear, surface-origination type peeling, and early peeling occur on the rolling surface of each roller of the one-way clutch. Premature peeling refers to peeling accompanied by a white texture change that occurs in the vicinity of the surface, or peeling in which cracks propagate in the vicinity of the surface in the direction opposite to the rolling direction of the rollers.
In addition, depending on the presence of water in the one-way clutch, the rolling surface of each roller, the rolling surface of the outer ring for clutch, and the rolling surface of the inner ring for clutch connected to the shaft to which the one-way clutch is attached It becomes easy to corrode.
JP 11-82688 A JP 2000-234638 A JP 2000-253620 A

  The present invention has been made to cope with such problems, and can effectively prevent separation on the rolling surface caused by water intrusion, and provide a one-way clutch having excellent long-term durability. Objective.

The one-way clutch of the present invention comprises a clutch outer ring and a plurality of rollers provided on an inner diameter surface of the outer ring, and is a one-way clutch attached to an output member. A one-way clutch that transmits only the oil to the output member via the rollers, wherein grease is enclosed in a clutch internal space in which the plurality of rollers are installed. A water-resistant grease comprising an additive containing at least an aqueous dispersant in a base grease made of a funnel, wherein the non-aqueous base oil is at least one selected from mineral oil, poly-α-olefin oil and alkyl diphenyl ether oil. A fat obtained by reacting an aromatic diisocyanate with an alicyclic monoamine and an aromatic monoamine. It consists of an aromatic urea compound obtained by reaction of an aromatic diisocyanate compound or an aromatic diisocyanate and an aromatic monoamine alone, and the aqueous dispersant contains a Ca sulfonate having a base number of 50 to 500. The amount of the water dispersant is such that the saturated moisture content of the water-resistant grease is set to 30% to 60% by weight.

The water dispersant contains sorbitan monooleate .
Further, it is characterized by containing 0.5 to 2 parts by weight of the Ca sulfonate and 0.2 to 1 part by weight of the sorbitan monooleate with respect to 100 parts by weight of the base grease .
Further, the thickener is characterized by comprising the alicyclic-aromatic urea compound .

The one-way clutch according to the present invention is a water-dispersing agent capable of dispersing water as fine particles in the grease in which the water-resistant grease enclosed in the clutch is a base grease composed of a non-aqueous base oil and a thickener. Therefore, water that has entered the clutch can be dispersed as fine particles. Therefore, even if water is mixed in the water-resistant grease of this clutch, it is possible to suppress the action of moisture that inhibits oil film formation. As a result, metal contact on the rolling surface is suppressed, early separation can be prevented, and a one-way clutch that requires long-term durability under conditions where water can easily enter due to splashing rainwater or a puddle. Can be suitably used.
Regarding the rust prevention action, the contact between the steel constituting the clutch and the massive water component can be reduced, so that the generation of rust can be suppressed.

  As a result of investigating the durability of one-way clutches used in places where there is a risk of water intrusion, it was found that grease with a controlled water content by adding a water dispersant that can disperse water as fine particles in the grease. It has been found that the enclosed one-way clutch can be maintained without lowering the lubrication performance of the rolling contact portion even when water enters. This is because grease with controlled saturation water content breaks down the oil film formed by the grease because the infiltrated water becomes minute water particles and is uniformly dispersed in the grease and trapped in the continuous phase grease. This is considered to improve the durability of the one-way clutch. The present invention is based on such knowledge.

The one-way clutch of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view of a one-way clutch according to an embodiment of the present invention. This embodiment is an example of a rotation transmission device 9 with a built-in one-way clutch that is a utilization form in which the one-way clutch 12 and the rolling bearing 1 are used in combination.
The one-way clutch built-in type rotation transmission device 9 includes a pulley 11 (outer diameter side rotation member) and a sleeve 10 (inner diameter side rotation member) connected to the output member as a pair of rotation members arranged concentrically with each other. Prepare. A pair of rolling bearings 1 and 1 and a one-way clutch 12 are provided between the inner diameter surface of the pulley 11 and the outer diameter surface of the sleeve 10.
The pulley 11 is formed in a cylindrical shape as a whole, and a part of an annular belt called a poly-V belt can be freely passed over with the cross-sectional shape of the outer diameter surface in the width direction as a waveform. On the other hand, the sleeve 10 is formed in a cylindrical shape as a whole, and is fitted and fixed to a rotary shaft of an auxiliary machine such as an alternator, and is rotatable together with the rotary shaft. Then, the rolling bearings 1 and 1 are installed at positions where the one-way clutch 12 is sandwiched from both sides in the axial direction at both axial ends of the cylindrical space located between the inner diameter surface of the pulley 11 and the outer diameter surface of the sleeve 10. At the same time, a one-way clutch 12 is installed at an axially intermediate portion of the cylindrical space.

  The one-way clutch 12 freely transmits the rotational force between the pulley 11 and the sleeve 10 only when the pulley 11 rotates at a predetermined relative speed with respect to the sleeve 10. The one-way clutch 12 includes a clutch outer ring 14, a clutch inner ring 13, a plurality of rollers 15, a clutch retainer 16, and a spring 21 (see FIG. 2). Of these, the clutch outer ring 14 is fitted and fixed to the intermediate inner diameter surface of the pulley 11 and the clutch inner ring 13 is fixed to the intermediate outer diameter surface of the sleeve 10 by interference fitting. Further, the intermediate inner diameter surface of the clutch outer ring 14 is a simple cylindrical surface, and the outer diameter surface of the clutch inner ring 13 is a cam surface 17. That is, a plurality of recesses 18 each called a ramp portion are provided at equal intervals in the circumferential direction of the outer diameter surface of the clutch inner ring 13, and the outer diameter surface of the clutch inner ring 13 is used as the cam surface 17.

  Further, a plurality of rollers 15 are supported between the intermediate inner diameter surface of the outer ring for clutch 14 and the cam surface 17, and each of the rollers 15 is supported corresponding to a slight displacement in the rolling and circumferential directions. A clutch retainer 16 is provided. The clutch retainer 16 is entirely made of synthetic resin, and its inner peripheral edge is engaged with a part of the cam surface 17 so as not to rotate at a higher speed than the clutch inner ring 13. At the same time, in the illustrated example, a convex portion 19 formed on the inner diameter surface of the end portion of the clutch retainer 16 is provided between the step surface 20 provided on the outer diameter surface of the sleeve 10 and the axial end surface of the inner ring 12 for clutch. The clutch retainer 16 is positioned in the axial direction by being held between the two.

As shown in FIGS. 2 (a) and 2 (b), which are sectional views in the circumferential direction of the one-way clutch, these rollers 15 are arranged in the circumferential direction between the rollers 15 and the retainer 16 for clutch. And a spring 21 for pressing in the same direction (direction in which each concave portion 17 becomes shallow). A water-resistant grease used in the present invention is enclosed around each roller 15.
As shown in FIG. 2A, when the outer ring for clutch 14 tries to rotate in the direction of the arrow (clockwise) in the drawing with respect to the inner ring for clutch 13, the roller 15 is moved by the spring action of the spring 21. The clutch inner ring 13 is driven by the wedge action of the cam surface 17 of the clutch inner ring 13 and the inner diameter surface of the clutch outer ring 14. In addition, as shown in FIG. 2B, when the outer ring for clutch 14 tries to rotate in the direction of the arrow (counterclockwise) in the drawing with respect to the inner ring for clutch 13, the inner ring for clutch 13 moves relative to the outer ring for clutch 14. Thus, the roller 15 is separated from the cam surface 17 of the inner ring 12 for clutch, and the outer ring 14 for clutch is idled with respect to the inner ring 13 for clutch.

  In addition, the pair of rolling bearings 1, 1 allows the sleeve 10 and the pulley 11 to rotate relative to each other while supporting a radial load applied to the pulley 11. As such rolling bearings 1 and 1, in FIG. 1, deep groove type ball bearings are used. That is, each of these rolling bearings 1, 1 has a deep groove type inner ring rolling surface 2 a on the outer diameter surface, as shown in detail in FIG. 3, which is a sectional view of a deep groove type ball bearing. The inner ring 2 fitted and fixed to the inner part, the outer ring 3 having a deep groove type outer ring rolling surface 3a on the inner diameter surface and fitted and fixed to both ends of the pulley 11, the inner ring rolling surface 2a and the outer ring rolling surface 3a, and a plurality of balls 4 provided so as to be able to roll while being held by a cage 5. Further, both end openings 8 a and 8 b of the space provided with the balls 4, which exist between the outer diameter surface of the inner ring 2 and the inner diameter surface of the outer ring 3, are sealed by the seal members 6, respectively. Further, water-resistant grease 7 used in the present invention is enclosed around each ball 4.

  In the one-way clutch built-in rotation transmission device 9 having the above-described configuration, the sleeve 10 is fitted and fixed to the end of the rotating shaft of an automotive electrical accessory such as an alternator, and the outer diameter surface of the pulley 11 is an annular belt. It is handed over. This annular belt is stretched over a driving pulley fixed to an end portion of an engine crankshaft or the like, and is driven by the rotation of the driving pulley. In the one-way clutch 12 assembled in such a state, when the traveling speed of the annular belt decreases, the pulley 11 and the rotating shaft can freely rotate relative to each other, and the traveling speed of the annular belt is constant. Or when it goes up, transmission of the rotational force from the pulley 11 to a rotating shaft is made free. As a result, even when the rotational angular velocity of the crankshaft fluctuates, the pulley 11 and the annular belt are prevented from rubbing to prevent the generation of abnormal noise called squeal and the life of the annular belt due to wear, and the alternator A decrease in power generation efficiency can be prevented.

  Using one-way clutch, when one of the electric motor and engine of the automotive electrical accessory is in the operating state and the other is in the stopped state, the rotational force from the one rotating shaft to the pulley 11 is reduced. Transmission can be made free and the other rotating shaft can be prevented from rotating. For example, by attaching the one-way clutch to the end of the drive shaft of the electric motor and crankshaft of the electric auxiliary equipment for automobiles, the one-way clutch can be used for an auxiliary equipment drive device when the engine is idling.

  As the one-way clutch of the present invention, in addition to the above-described combined type in which a bearing (or another roller) and a one-way clutch are combined, a bearing or the like is not used together when the radial load applied to the one-way clutch is small. The thing of a form etc. can also be used.

The water resistant grease used in the present invention is a water resistant grease obtained by blending an additive containing a water dispersing agent capable of dispersing water into a base grease composed of a non-aqueous base oil and a thickener, and enters a bearing. It has a certain affinity for incoming water. A numerical value indicating this affinity was called “saturated water content” and defined as the following formula.

Saturated water content (wt%) = maximum water content dispersible in grease x 100 / (grease weight + maximum water content dispersible in grease)

In the water resistant grease used in the present invention, the blending amount of the water dispersant is such an amount that the saturated moisture content of the grease represented by the above formula can be made 30 to 60% by weight, preferably 40 to 50% by weight. Within this range, inhibition of oil film formation due to moisture can be suppressed.
If the amount of the water dispersant is less than 30% by weight, it becomes difficult for water to be taken in, and the infiltrated water exists as large water droplets inside the bearing and inhibits oil film formation. On the other hand, if the blending amount is more than 60% by weight, a large amount of moisture is retained inside the bearing, and rust is generated.

  In addition, the amount of the water dispersant should be such that the particle size of the water dispersed by the water dispersant measured at a water content of 20% by weight is 50 μm or less with respect to the total amount of grease and the total amount of water. Is preferred. If the water droplets are 50 μm or less, the water does not inhibit the formation of the oil film by the water-resistant grease. Preferably it is 30 micrometers or less, More preferably, it is the range of 5-25 micrometers. If it exceeds 50 μm, oil film formation is inhibited and the bearing life is extremely shortened. The water particle diameter in the present invention is a numerical value obtained by measuring the diameter of water droplets dispersed in a base grease having a water content of 20% by weight spread on a glass plate under a load of 600 N with a microscope. .

In the present invention, a surfactant can be used as the water dispersant capable of controlling the saturated water content. The surfactant is used to disperse water in the grease and render the water harmless so that the oil film does not break or rust even when water enters the one-way clutch. The water that has entered the grease is dispersed in the grease as fine water particles by the surfactant. Since grease can exist as a continuous phase, it is thought that oil film breakage does not occur.
Similarly, water particles, which are discontinuous phases confined in grease, which is a continuous phase, have a very low probability of coming into contact with the steel constituting the one-way clutch body, and water particles adhering to steel with low probability are also one-way clutches. It is considered that the steel cannot be rusted because it is immediately replaced with the continuous phase grease by the rotation of the rolling elements in conjunction with the rotation of the main body.

  The surfactant that can be used in the present invention is a W / O (water phase dispersed in an oil phase (grease)) type interface that easily traps water particles as a discontinuous phase in a grease that is a continuous phase. The HLB (Hydrophilic-Lipophilic Balance) value representing the degree of affinity of the surfactant for water and oil is preferably in the range of 5-18.

  Specific examples of the surfactant used in the present invention include glycol surfactants such as polyalkylene glycols, carboxylic acid alkylene glycols, and carboxylic acid polyalkylene glycols, glycerin glycerin, and polyoxyalkyl carboxylates. Glycerin surfactants such as glycerin and glyceryl carboxylates, glyceryl surfactants such as polyglyceryl carboxylates and polyoxyalkylene glyceryl carboxylates, polyoxyalkylene alkyl ethers, and polyoxyalkylene alkyl ether carboxylates Ether surfactants such as carboxylic acid polyoxyalkylene alkyl ether diesters and sorbitan ester surfactants, polyoxyalkylene hardened castor oil, carboxylic acid polyoxyal Castor oil surfactants such as alkylene hydrogenated castor oil-based, carboxylic acid polyoxyalkylene Rent trimethylolpropane-based surfactant, metal sulfonate surfactant, sorbitan ester surfactant and the like. These surfactants may be used alone or in combination of two or more.

In the present invention, among the above surfactants, it is preferable to use a metal sulfonate surfactant, a carboxylic acid polyalkylene glycol surfactant, or a sorbitan ester surfactant. Particularly preferred are Ca sulfonate, polyethylene glycol stearate, sorbitan monooleate and the like.
The metal sulfonate surfactant, carboxylic acid polyalkylene glycol surfactant, or sorbitan ester surfactant can control the saturated water content within the range of 30 to 60% by weight within the range of the following blending amount. it can.

  The amount of the surfactant (aqueous dispersant) that can be used in the present invention is such an amount that the saturated water content of the grease can be adjusted to 30 to 60% by weight as described above. Specifically, it is increased with the non-aqueous base oil. The amount is preferably 0.4 to 4 parts by weight with respect to 100 parts by weight of the base grease comprising the agent. More preferably, it is 1 to 4 parts by weight. If the amount is less than 0.4 parts by weight, the saturated water content may not be 30% by weight or more, and it is difficult to obtain the desired effect sufficiently. If the amount exceeds 4 parts by weight, the saturated water content may exceed 60% by weight, and the desired effect such as the oil film formation rate will reach its peak, reducing the grease characteristics such as the one-way clutch life. .

The Ca sulfonate that can be used in the present invention preferably has a base number in the range of 50 to 500. A base number shows the quantity of the basic substance contained in 1 molecule, and becomes a high numerical value, when there is much quantity of Ca which an additive contains. Basic Ca sulfonate can not only provide rust prevention performance but also extreme pressure performance.
For example, in the present invention, when 0.5 to 2 parts by weight of Ca sulfonate is blended with 100 parts by weight of the base grease, the extreme pressure performance becomes insufficient when the base number is less than 50, and the base number exceeds 500. No further effect can be expected.

  The sorbitan monooleate that can be used in the present invention is a nonionic surfactant, has an HLB value of about 9 indicating the degree of affinity of the surfactant with water and oil, and has lipophilic properties. Have The sorbitan monooleate is preferably used in combination with the Ca sulfonate.

In the present invention, the combination amount of Ca sulfonate and sorbitan monooleate as the surfactant is 0.5 to 2 parts by weight of Ca sulfonate and 0.2 to 1 part by weight of sorbitan monooleate with respect to 100 parts by weight of the base grease. Part.
Moreover, when using these independently, it is preferable to mix | blend Ca sulfonate 1.5-4 weight part and sorbitan monooleate 0.4-2 weight part.
By using both in the above range, the saturated moisture content of the water-resistant grease can be controlled to 30 to 60% by weight. In addition, the desired effect such as the oil film formation rate has reached its peak, and there is no fear that the grease characteristics such as the bearing life will deteriorate.

Non-aqueous base oils that can be used in the present invention are mineral oils such as spindle oil, refrigerating machine oil, turbine oil, machine oil, dynamo oil, highly refined mineral oil, liquid paraffin oil, GTL oil synthesized by Fischer-Tropsch method, polybutene oil , Poly-α-olefin (hereinafter referred to as “PAO”) oil, alkylnaphthalene oil, hydrocarbon synthetic oil such as alicyclic compound, or natural oil, polyol ester oil, phosphate ester oil, polymer ester oil, aromatic Non-hydrocarbon synthetic oils such as group ester oil, carbonate ester oil, diester oil, polyglycol oil, silicone oil, polyphenyl ether oil, alkyl diphenyl ether oil, alkylbenzene oil, and fluorinated oil can be used. These non-aqueous base oils can be used alone or in combination of two or more.
In consideration of lubricating performance and price, among these non-aqueous base oils, it is preferable to use mineral oil, PAO oil, or alkyl diphenyl ether oil.

The non-aqueous base oil that can be used in the present invention is liquid at room temperature and has a kinematic viscosity at 40 ° C. of 20 to 200 mm ² / sec. Preferably, it is 30-120 mm < ² > / sec. If it is less than 20 mm ² / sec, the non-aqueous base oil deteriorates in a short time, and the deteriorated product promotes the deterioration of the entire non-aqueous base oil. Become. On the other hand, if it exceeds 200 mm ² / sec, the temperature rise of the clutch increases due to the increase in torque, which is not preferable.

In the present invention, the blending ratio of the non-aqueous base oil in 100 parts by weight of the base grease is preferably 60 to 99 parts by weight, more preferably 70 to 95 parts by weight.
When the blending ratio of the non-aqueous base oil is less than 60 parts by weight, the grease is hard and the lubricity at low temperatures is poor. If it exceeds 99 parts by weight, it will be soft and leaky.

  Thickeners that can be used in the water-resistant grease in the present invention include benton, silica gel, fluorine compound, lithium soap, lithium complex soap, strong lucium soap, calcium complex soap, aluminum soap, aluminum complex soap and other soaps, diurea compounds, Examples include urea compounds such as polyurea compounds. In consideration of heat resistance, cost, and the like, a urea compound is desirable.

式中においてＲ² は、炭素原子数 6〜15 の芳香族炭化水素基を、Ｒ¹ およびＲ³ は、互いに同一であっても異なっていてもよく、それぞれ炭素原子数 6〜12 の芳香族炭化水素基または炭素原子数 6〜20 の脂環族炭化水素基およびまたは炭素原子数 6〜20 の脂肪族炭化水素基から選ばれた少なくとも一つの基を、それぞれ示す。
ウレア系化合物は、イソシアネート化合物とアミン化合物とを反応させることにより得られる。反応性のある遊離基を残さないため、イソシアネート化合物のイソシアネート基とアミン化合物のアミノ基とは略当量となるように配合することが好ましい。 The urea compound is represented, for example, by the following formula (1).

In the formula, R ² is an aromatic hydrocarbon group having 6 to 15 carbon atoms, and R ¹ and R ³ may be the same or different from each other, and each of them is an aromatic group having 6 to 12 carbon atoms. At least one group selected from a hydrocarbon group or an alicyclic hydrocarbon group having 6 to 20 carbon atoms and / or an aliphatic hydrocarbon group having 6 to 20 carbon atoms is shown.
A urea compound is obtained by reacting an isocyanate compound and an amine compound. In order not to leave a reactive free radical, the isocyanate group of the isocyanate compound and the amino group of the amine compound are preferably blended so as to be approximately equivalent.

The diurea compound represented by the formula (1) can be obtained, for example, by reaction of diisocyanate and monoamine. Diisocyanates include phenylene diisocyanate, diphenyl diisocyanate, diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, 2,4-tolylene diisocyanate, 3,3-dimethyl-4,4-biphenylene diisocyanate, octadecane diisocyanate, decane diisocyanate, hexane diisocyanate. Examples of the monoamine include octylamine, dodecylamine, hexadecylamine, stearylamine, oleylamine, aniline, p-toluidine, cyclohexylamine and the like.
In the present invention, an alicyclic-aromatic urea compound or an aromatic urea compound obtained by a reaction of an aromatic diisocyanate with an alicyclic monoamine and an aromatic monoamine, or an aromatic monoamine alone is preferable. Particularly preferably, cyclohexylamine is used as the alicyclic monoamine and aniline is used as the aromatic monoamine.

For example, after sufficiently reacting monoamine acid and diisocyanate in a non-aqueous base oil at about 70 to 120 ° C., the temperature is raised and maintained at 120 to 180 ° C. for about 1 to 2 hours, and then cooled. , Homogenizers, three roll mills, etc. are used to obtain a base grease for blending various compounding agents.
In the present invention, the blending ratio of the thickener in 100 parts by weight of the base grease is preferably 1 to 40 parts by weight, more preferably 3 to 25 parts by weight. If the blending ratio of the thickener is less than 1 part by weight, the thickening effect will be reduced and it will be difficult to make grease, and if it exceeds 40 parts by weight, the grease will be too hard and the desired effect will not be obtained.

  To the water-resistant grease used in the present invention, known additives other than the above-mentioned surfactant (water dispersing agent) can be added as necessary within the range not impairing the function. Examples of additives include extreme pressure agents such as organic zinc compounds and organic molybdenum compounds, antioxidants such as amine-based, phenol-based and sulfur-based compounds, anti-wear agents such as sulfur-based and phosphorus-based compounds, and polyhydric alcohols. Examples thereof include rust preventives such as esters, viscosity index improvers such as polymethacrylate and polystyrene, solid lubricants such as molybdenum disulfide and graphite, and oily agents such as esters and alcohols. Moreover, metal fine powders, such as molybdate, an organic acid salt, aluminum, and copper, can also be mix | blended as an additive which suppresses early peeling with a white structure | tissue change. These can be added alone or in combination of two or more.

  Among the above additives, the water resistant grease used in the present invention preferably contains an extreme pressure agent for imparting extreme pressure performance and an antioxidant for suppressing oxidative degradation. It is particularly preferable to use zinc dithiophosphate as the extreme pressure agent and an amine antioxidant as the antioxidant.

式中においてＲ は、アルキル基を示す。アルキル基としては、一級アルキル基、二級アルキル基およびアリール基が挙げられるが、水に対する安定性や摩耗防止性等のバランスのよい二級アルキル基を用いることが好ましい。 Examples of zinc dithiophosphate include zinc dialkyldithiophosphate represented by the following formula (2), which is added to impart extreme pressure performance of grease.

In the formula, R 1 represents an alkyl group. Examples of the alkyl group include a primary alkyl group, a secondary alkyl group, and an aryl group, but it is preferable to use a secondary alkyl group having a good balance such as stability against water and wear resistance.

  The compounding amount of zinc dithiophosphate is preferably 0.5 to 2.0 parts by weight based on 100 parts by weight of the base grease. Most preferably, it is 2.0 parts by weight with respect to 100 parts by weight of the base grease. If the amount is less than 0.5 parts by weight, the extreme pressure performance becomes insufficient, and it is difficult to obtain the desired effect sufficiently, and even if added over 2.0 parts by weight, no further effect can be obtained. Can not.

Examples of amine antioxidants include phenyl-1-naphthylamine, phenyl-2-naphthylamine, diphenyl-p-phenylenediamine, dipyridylamine, phenothiazine, N-methylphenothiazine, N-ethylphenothiazine, and 3,7-dioctylphenothiazine. , P, p′-dioctyldiphenylamine, N, N′-diisopropyl-p-phenylenediamine, and the like.
The compounding amount of the amine antioxidant is preferably 0.5 to 2.0 parts by weight with respect to 100 parts by weight of the base grease. When the amount is less than 0.5 parts by weight, the antioxidant performance becomes insufficient, and it becomes difficult to obtain the desired effect sufficiently, and even if added over 2.0 parts by weight, no further effect can be expected. Most preferably, it is 1 part by weight per 100 parts by weight of the base grease.

The present invention will be specifically described with reference to examples and comparative examples, but is not limited to these examples.
Reference Example 1 to Reference Example 7, Example 1 to Example 6, and Comparative Example 1 to Comparative Example 6
A mineral oil / urea base grease (JIS consistency No. 2 grade, consistency: 265 to 295) in which a urea compound is uniformly dispersed as a thickener in a mineral oil which is a non-aqueous base oil was prepared.
In 2000 g of mineral oil (Nippon Oil Co., Ltd. turbine 100, kinematic viscosity at 40 ° C .: 100 mm ² / sec), 2000 g of diphenylmethane-4,4′-diisocyanate, 86.2 g of aniline and 91.7 g of cyclohexylamine And the resulting urea compound was uniformly dispersed to obtain a base grease. Additives were added to the base grease in the formulation shown in Table 1 to obtain a test grease.

  The obtained grease for testing was subjected to an oil film formation rate test, a bearing life test, and a saturated water content measurement described below, and an oil film formation rate, a bearing life time, a saturated water content, and whether or not rust was generated were measured. The results are also shown in Table 1.

<Oil film formation rate test>
Bearings used: Angular contact ball bearings 7006ADLLB (outer ring: S53C, inner ring: SUJ2) were used to evaluate the water-resistant grease used in the one-way clutch of the present invention.
Test conditions: 1.0 g of the obtained grease for test is sealed in an angular ball bearing 7006ADLLB, and is rotated at a radial load of 8000 N, an axial load of 3000 N, and a bearing rotational speed of 1000 rpm. The oil film formation rate of the test grease when water was poured for 10 hours was measured. The oil film formation rate was measured by the electric resistance method.

<Bearing life test>
Bearing used: The water-resistant grease used in the one-way clutch of the present invention was evaluated using an angular ball bearing 7006ADLLB (outer ring S53C, inner ring SUJ2).
Test conditions: 1.0 g of the obtained grease for test is sealed in an angular ball bearing 7006ADLLB, and is rotated at a radial load of 8000 N, an axial load of 3000 N, and a bearing rotational speed of 1000 rpm. The bearing life when water was poured was measured. The bearing life was defined as the time until one of the outer ring rolling surface, inner ring rolling surface, and steel ball was damaged and the vibration increased.

<Saturated water content measurement>
Add a fixed amount of water to the test grease by changing the mixing ratio of water by 5% by weight, and manually stir using a microspatel to obtain the maximum amount of water that could disperse the added water. The saturated water content was calculated using the formula. To determine whether it was dispersed, collect test grease on a glass plate, place a spacer shim with a thickness of 0.025 mm on both ends of the glass plate, and sandwich it with another glass plate from above. When the test grease was spread and observed with a microscope, the largest water droplets present in the grease were considered to be dispersed when the particle size was 50 μm or less.

Saturated water content (wt%) = maximum water content dispersible in grease x 100 / (weight of test grease + maximum water content dispersible in grease)

Reference Example 6
In a reaction vessel, 11.7 g of PAO oil (Nippon Chemical Co., Ltd., Sinfluid 801: Kinematic viscosity at 40 ° C .: 46 mm ² / sec), 231.7 g of diphenylmethane-4,4′-diisocyanate and 86.2 g of aniline And 91.7 g of cyclohexylamine were reacted to uniformly disperse the produced urea compound to obtain a base grease. Additives were added to the base grease in the formulation shown in Table 1 to obtain a test grease. The same items as in Reference Example 1 were measured for the obtained test grease. The results are also shown in Table 1.

Reference Example 7
In a reaction vessel, in 1850 g of alkyl diphenyl ether oil (LB100 manufactured by Matsumura Oil Co., Ltd., kinematic viscosity at 40 ° C .: 100 mm ² / sec), 231.7 g of diphenylmethane-4,4′-diisocyanate and 86.2 g of aniline Then, 91.7 g of cyclohexylamine was reacted, and the resulting urea compound was uniformly dispersed to obtain a base grease. Additives were added to the base grease in the formulation shown in Table 1 to obtain a test grease. The same items as in Reference Example 1 were measured for the obtained test grease. The results are also shown in Table 1.

As shown in Table 1, a high oil film formation rate is obtained in a region where the saturated water content is 30 to 60% by weight (particularly 40 to 50% by weight).
When water is mixed in, grease with saturated water content of less than 30% by weight or grease with more than 60% by weight impairs the formation of an oil film, which causes metal contact and rust. If it is 30 to 60% by weight, an oil film can be formed, so there is little risk of metal contact, so the life is long, and the occurrence of rust can be suppressed.

  In the one-way clutch of the present invention, a base dispersant composed of a non-aqueous base oil and a thickener is blended with a water dispersant capable of dispersing water in the grease, and the saturated moisture content of the grease is 30 to 60. Since water-resistant grease controlled by weight percent is enclosed, even if water enters the grease during operation, it can suppress the action of moisture that hinders the formation of an oil film on the grease and suppresses early peeling. Even if the lubrication conditions become severe, a long life can be obtained. For this reason, it can be suitably used as a one-way clutch used in an automobile electrical accessory or the like that is required to have long-term durability as well as wear resistance in an environment where there is a possibility of water intrusion.

It is sectional drawing of the one way clutch which concerns on one Example of this invention. It is a circumferential sectional view of a one-way clutch. It is sectional drawing of a rolling bearing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Deep groove ball bearing 2 Inner ring 3 Outer ring 4 Rolling body 5 Cage 6 Seal member 7 Water resistant grease 8a, 8b Opening 9 One-way clutch built-in type rotation transmission device 10 Sleeve 11 Pulley 12 One-way clutch 13 Clutch inner ring 14 Clutch outer ring 15 Roller 16 Clutch retainer 17 Cam surface 18 Concave portion 19 Convex portion 20 Stepped surface 21 Spring

Claims (2)

A one-way clutch provided with an outer ring for clutch and a plurality of rollers provided on an inner diameter surface of the outer ring, and attached to an output member, wherein only one-way torque of the outer ring for clutch is transmitted through the roller. A one-way clutch mounted on an automotive electrical accessory that transmits to an output member,
Grease is enclosed in an internal space of the clutch in which the plurality of rollers are installed, and the grease is formed by blending an additive containing at least an aqueous dispersant with a base grease composed of a non-aqueous base oil and a thickener. Water resistant grease,
The non-aqueous base oil comprises at least one oil selected from mineral oil, poly-α-olefin oil and alkyl diphenyl ether oil;
The thickener is an alicyclic-aromatic urea compound obtained by a reaction of an aromatic diisocyanate with an alicyclic monoamine and an aromatic monoamine, or a reaction of an aromatic diisocyanate with an aromatic monoamine alone. It consists of an aromatic urea compound obtained,
The water dispersant contains Ca sulfonate having a base number of 50 to 500 and sorbitan monooleate , and the amount of the water dispersant is such that the saturated moisture content of the water resistant grease is set to 30 to 60% by weight. The
A one-way clutch comprising 0.5 to 2 parts by weight of the Ca sulfonate and 0.2 to 1 part by weight of the sorbitan monooleate with respect to 100 parts by weight of the base grease .   The one-way clutch according to claim 1, wherein the thickener comprises the alicyclic-aromatic urea compound.

Images